I've been using the hell out of this thing lately. I'm putting together a new rig, and while I had everything wired up on the bench to set up the OSD, I noticed the receiver RSSI would not drop below 50% with the radio off.
I turned on the RF explorer and sure enough, the noise floor was off the charts, which explains the high RSSI. Yesterday I had a similar issue caused by my laptop, but this time the laptop wasn't running. I then started checking each component one by one to try to figure out the cause. You may find the results interesting..
Span is set from 432-446MHz, scaled from -120dBm to -40dBm ("very loud!")
Solid black plots are real time readings, plots showing a line above are peak hold mode. "Clearance" is how far I had to move the explorer back to no longer pick it up, so I'm assuming this is how far away it should be from your receiver to not affect it.
This is not inside a faraday cage, and I am not an RF engineer. This is "putting stuff next to the explorer to see what happens" type science.
Baseline, nothing powered
Punch RC brand ESC (80a, 5a SBEC), clearance 16"
PZ0420N 600TVL camera from securitycamera2000, clearance 14"
"800mw" 1280MHz with 1.3GHz low pass filter. No change to noise floor.
Skylark Tiny 2 OSD board, clearance over 3 feet!
Peak hold after a minute
Peak relative to background noise after unplugging battery
I am really hoping something is wrong with this OSD. It makes a faint high pitched whistle while powered, somewhat like an old tube TV. I thought maybe it was the switching frequency, however the last one we set up (mounted in my brother's plane) does not whistle or emit any of this hash.